摘要 |
The invention is a process for monitored cross-linking of unsaturated polyester resins in the presence of a metal-ion-containing accelerator and an organic peroxide initiator, complemented by promotor in some cases. According to this process, the cross-linking is carried out in the presence of one of the compounds from the group consisting of alizarin, sodium alizarinesulfonate, 3-nitroalizarin, chinizarine, or purpurin, where the substituents are H atoms or OH, NO2, SO3H, or SO3Na groups with the restriction that at least one of them should be other than H, which is present in a ratio of from 0.005 to 0.5, preferably 0.01 to 0.1 percent (mass/mass), compared to the mass of the polyester resin, and cross-linking is trailed by the color change in the system. The invention permits all of the chemical-technological processes involved in the processing of unsaturated polyester resins to be monitored visually.
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